5 Ways to Trim a Cup or Cylinder on the Wheel- Demos Explained! (And Two Additional Bonus Methods!)

Welcome back to my home studio. I am Karen with a Walsh of Karen's Pots and Glass, and this video today is going to be showing five different ways that you can trim a cup or a cylinder on the potter's wheel. So in this video, I am showing the different methods that I show my students at my high school of trimming in the order that I present them to them as most likely for them to do. So the first method that I show is using a Giffin Grip. A Giffin Grip is a great tool that is used for centering and holding a pot in place. So that is the first method that they often go to. The second method is using a chum, which is a domed piece of centered clay that you rib off and you put your piece on top of it. I really love using chums, especially for forms that are perhaps a little bit wider, a little less tall. Chums are great for that. The third method that I show is the method that I first learned when I was a beginning potter in college, and that is using lugs to hold the rim in place. Lugs are a little bit harder for my students because sometimes they're not really paying attention to how moist is the pot, and if it's a little bit too moist, they can squish the rim. If it's a little too dry, they can crack the rim. The next method that I'm showing is how to use a sticky bat. A sticky bat is a Creative Industries tool, and it's a bat which is sticky, and it just helps to hold your pot in place, but you do have to keep your other hand on it, your non-trimming hand on it, to keep it stable so it doesn't fly off. And then lastly, I'm going to be showing just a technique, just with a little film of water that helps to hold it in place, even though you do have to be firm about making sure that you're not moving it. Those last two methods are most difficult for my students, just the water method and the sticky bat method, because with a taller form like a cup or a cylinder, sometimes if they aren't carefully holding it, it can tip over. And then I show two other bonus things at the end, even though I'm not showing them with cups, and that is talking about a chuck and a foam bat. So hopefully you will find this somewhat beneficial. I talk about how to cut the foot and how to get it evenly cut, because a lot of times beginners will have the difficulty of making their foot wobbly. It might be thick on one side, thin on the other, and that's because they haven't brought the cut down from the bottom. They bring it in from the outside. So hopefully you can learn something new on this. Please drop me any questions below that you have, and don't forget to like and subscribe to my channel. Thanks! This method is going to be using a Giffin Grip in order to trim. A Giffin Grip is designed in two parts to go...it snaps onto the wheel head. Now I want to show you what the inside of the Giffin Grip looks like, so you have an understanding. The top and the bottom will spin independently of one another, and you can see that the bottom actually is engineered with this screw type of mechanism. Now this happens to be a right-handed Giffin Grip. If I were left-handed, they do make left-handed Giffin Grips, and I do have one of those at school for my kids. I'm just going to reinstall this little washer and holder right there. Now when I go to put it on my wheel, they do have to be sized, I should mention that. They are sized for specific size wheel heads. So this one is sized for my Pacifica wheel head. I have at school, I have some that are sized for the Brents, some that are sized for Pacificas, and they are different. So students, pay attention when they are marked for Brent or Pacifica that you are using the right one. Now, note where your bat pins are, and then on the back of it, if you line up your fingers, say with the triangles on the back, and you align that with the bat pins, it will go up inside of there. If you don't actually align it with one of those holes on the back, it can get stuck on a bat pin and be crooked. One of the things that I always tell my kids is to double check it, place your finger right next to it. If you see it's weaving up and down, then you know you're probably stuck on a bat pin and you need to fix it. Now when you begin, you want to align the top plate with the groove that's on the bottom. Now there are two grooves, technically. If I look over here, there's another groove here, but this is not as big. I want the deep initial groove that goes in there. Now for the Giffin Grip, for doing cups, I could use it with the rubber side facing in, but then it's only going to be held down low. Now I am going to trim a tall form, so I would like to hold it up a little bit higher. So in that case, I'm going to turn it around with the other side, which has like a little hole, and that holds the rods and the little hands. And then if I hold, I'm going to hold the bottom here, I'll do it over here, so I'm going to hold the bottom plate so the bottom plate doesn't move, and then I'm going to screw the top in, going clockwise, and that will bring in all of these at the same time. It's key that you always start the little holders at the same point. If you have them at different points, say for instance in my classroom, sometimes the kids will pull the top plate up and it disengages it from the bottom plate, and then they stick it back on there. Well, these little guys have moved by that point, so if you just put them on randomly, you could have one that's farther out and one that's farther in, you will never get your piece fully centered until you correct that. Here in my home studio, I keep all of my little Giffin Grip attachments together in my little box. At school I have a much larger box that we share for all the different Giffin Grips. Now I am using the, I guess those are probably four inch rods, and the hands are on the bottom, and you've got to make sure that it goes all the way into the hole there, and then I can position this up here, and I want to make sure that it's in a position where it's going to hold it securely, so as I push that in, that will hold it nice and securely. Now let's take a look here at the interior. Keep in mind that the interior opening, the diameter of the interior, does determine the placement of the foot. I have another video on foot placement, if you would like to watch that, where it kind of guides. By determining where the interior diameter is for your foot, it will help to prevent your walls from being unnecessarily thick. Alright, so now I'm just going to snug that in. I have made marks with my fingernails of where the interior width is, so then I know that is where I'm going to be trimming. Now the nice thing about the Giffin Grip is that it's pretty snug, and it's not going to tip over. Before I actually start trimming, I want to show you one other thing. In my classroom, as well as here in my home studio, I have made one of these shields out of a few of the flexible cutting boards that I got at the Dollar Store, at Dollar Tree actually. If I place that in my pan, and you can see I have a notch that will go over the place that sticks up on my splash pan. As I put that there, it will help to collect my trimming so they don't go all over my floor. As I start this, I start with a medium to low speed. I don't need to go super fast as I do this. A couple of things that I want to just review with you. Number one, try to lock your hands together. You can see, whatever way is most comfortable, try to lock your hand. If your hand is independent out here, and it's not locked to anything, it's going to be hard to keep it even. I lock my hands together. Secondly, if you can also touch the tool to your left hand. My right hand is holding the tool, but yet I'm going to brace it with the left hand. That's helpful. Then number three, if you can also rest the bottom of your left hand right on the pot, that will help. As I begin this, I'm using only the corner of this tool. As it comes in here, I use just the corner. Note both my hands are locked together. Note that my left hand is bracing the tool, and my left hand is also braced on the pot bottom. I really have three points of bracing. Tool to hand, hand to hand, and then hand to cup. So I'm very braced, and my elbows are firmly locked. If you're working on a lower wheel than mine, you might be able to do this by leaning over on your elbows. I do have my wheel up, though, so I don't use my legs as frequently for trimming. So there we go. I've gotten the exterior of the foot, and now I can tidy it up a little bit. I'm just going to bring this in. I'm making an undercut. The reason I often make an undercut is so when I glaze it, if I want to hold it by the bottom, it makes it slightly more accessible. And then I can come down. Now again, hands should be braced together when you do this. You can see the benefit for the shield. Now I am going slowly, but if I were to speed it up, that stuff does fly off. So the shield will help to catch probably at least half of the stuff that would normally go on the floor, because I'd like for it to go into my splash pan rather than on the floor. So before I do the very bottom, I am doing the exterior of the foot because I want to make that tidy and get rid of any obvious lines of my tools. I want it to be super smooth. And then I can also take my rib over it. So I'm going to use one of the Red Mud Tools ribs. This clay, I should have mentioned, is leather hard. All the clay that I'm trimming today should be stiff enough that it can withstand this without fear of collapse. Much drier though, and it might be too dry to put on a handle, so you really have to pay attention and watch the moisture of your clay to get it to the right point. Now I can work on the very bottom of this. And I want to think about the width of the foot being about the same width as the wall that I threw. If your foot is really, really fat, that means that it might not dry evenly. So I like to make sure that the floor, the walls, and the foot are all relatively the same moisture. Now if you remember, when I threw this, I tried to keep my walls, I mean my floor, at about 3 eighths of an inch to a half an inch thick. That shouldn't allow me to get a nice depth on my foot. So it looks pretty good. I don't see any noticeable lines. It looks pretty smooth. On the interior, I could certainly smooth that with a rib if I wanted to. My beginners often have difficulty and they get nervous smoothing the inside with a rib because they're afraid they're going to gouge it. That is a legit concern. One of the things about trimming is you always want to make sure that you're trying to keep it even and not gouge. If you are holding it a little unevenly, you could go down and poke a hole right smack dab through the bottom. So here is my foot and it looks nicely even and I'm ready to set that aside so I can put a handle on that a little later. I'm going to keep this covered until I'm ready to put the handle on it. So on this cup, once again, just like I did on the other one, I'm going to mark where the interior angle is happening on the inside and that's going to indicate that will be the placement for my foot. One of the biggest mistakes that my students make is they tend to make the foot too narrow. Like they start cutting and they accidentally cut it off. So to prevent that, you want to make sure that you're holding extremely steady hands, that you have three points of contact, hand to hand, hand to tool, so the left hand is bracing against the tool, and then hand to cup or hand to pot, I should say. So let's start off by going straight down. So this is just like I did on the previous one. I go straight down to establish the exterior of the foot ring. Now for this one, my walls are fairly straight on the inside. They might taper a little bit. I am just going to bring this in and then start to bring that up. Now I'm just going to refine the exterior of the foot ring. Now I would normally take off a little bit more of the weight of the clay on the day that I'm throwing it. But my students do struggle because they're beginners, so they often have a fair amount of clay that they have to take off, just like what I did on this one. Now if you're a little bit dry and you want to rib it, you can always add just a teensy bit of moisture either by adding it with a sponge or perhaps dipping your rib in a little bit of water. And then I'm compressing with my finger on the exterior of the foot ring as opposed to the rib, because sometimes, again, my kids might have difficulty holding that rib without gouging. Now once I have done the exterior, then I want to do the interior. Again, hands locked together, I go straight down from the top. Now notice that when I first made the cut on the exterior, I went straight down from the top. On the inside of this one, I go straight down from the top. The purpose is, if you go straight down on both sides, your foot will be parallel. But if on the exterior, if you just come in from the outside, that's not straight down. If you come in from the outside, your exterior still may be wobbly. So just remember, make those cuts going straight down and they should be parallel. So I go straight down for the interior of the foot. When I feel like I've maybe done about half of the thickness of the foot, then I can start to trim away some on the inside. Here I've just taken my finger to compress the bottom of the foot ring because it had a few rough things on it. Now when I go across to the middle, my goal is I just want to make this flat. I want to get rid of basically that little disc in the middle. So you could do it a number of ways. You could use just the corner, you could use the flat part of the tool, whatever part is easiest for you to do that without gouging. If you gouge, you can get your tool caught and you can poke all the way through. Now notice, again, I have the tool held by my hand and then my hand is braced on the pot. That will help to prevent gouging. At this point, you certainly could rib the bottom if you're comfortable using a rib on the bottom or you could probably just compress. If your clay is too soft, you can poke through real easily. So it really needs to be leather hard. If it's too thin, you can poke through. So again, you just want to be attentive to how thick are you throwing that bottom so you have an understanding. Now one of the things that people can do sometimes is they can tap. Sometimes when you tap, you can hear a difference. Sometimes you can feel a difference. So I think I'm fine with this the way it is. There's my trimmed bottom to that cylinder. And again, I will set this aside to get a handle later. Now for this second method of trimming, I'm going to be showing trimming using a chum. And I'm just putting my batmane on and I'm going to center my hunk of clay by coning. And I'm going to create a dome that will become my chum. A chum is a dome of clay which is designed to fit up inside of a piece that you set on it. Now a chum is thrown and then ribbed really well because you do not want any moisture at all to touch your piece. If you left the slip on there, you would get stuck and damage your rim. Now forms that work great on chums are ones that are perhaps just a little bit shorter. I wouldn't use necessarily super tall forms on a chum, but it is a pretty secure way. One of the things that I like to do before I anchor the pot on there is I usually like to make a few lines. You could use a needle tool, I just used my thumbnail to make a few concentric lines so it will help me to place it on there evenly. Just like I did before, I'm going to take my fingers, make a little mark where the interior of the form has the angle on the inside. Now before I really press that down, I just want to make sure it looks even on those concentric lines that I did. That's pretty good. So by just giving it a nice firm little press onto the chum, oh and you don't want the chum to be out of super wet clay either because if it is really wet clay it will just start to collapse. Now I anchor my hands in the same manner that I did before. Hands anchor together, the left hand anchored to the tool and my left hand sits on the bottom. This helps me to keep it stable and it allows it to spin freely under my fingertips. So I'm doing the exterior of the foot ring first. Remember to go straight down from the top and then I'm going to clean up the exterior. There are so many different ways that you can design and style a foot ring. I encourage you to look online to see ones that really appeal to you. Again, I often create a slight undercut because I enjoy the ability to pick up the piece by the foot. If I wanted to say dip the rim in a glaze. Once I've refined the exterior, then I'm going to move to the inside and again straight down from the top. One of the issues that I should point out is if you take your pot off to say look at it and you put it back on, if you don't have it back on in exactly the right configuration, the right direction that it was before, you'll probably end up with a foot ring that is uneven. So you want to pay attention to that. Try to get your foot ring cut before you take it off to check it. Okay now, I just got it hooked and so you can see it just went a little bit wobbly. So I need to just kind of anchor that back down. Here we go. I'm just going to round the edge of my foot ring as it starts to go under. I like to have a nice rounded edge on the foot ring. That way I don't have any corners, sharp spots, parts that might be more likely to say scratch or perhaps get chipped. If it has a sharp corner, you could end up by chipping it easily. And lastly, with a little bit of water here, I'm going to add just a little bit of water to that and compress that with my baby red rib. Now if you have clay with grog, you have to be very careful not to just sponge it at this point because if you have sponged groggy clay, it will remove the fine particles of clay and leave behind the thick grog. Oops. Here we go again. Again, if you ever just put a little bit more side pressure, it'll knock it a little bit loose there. And then the last little bit that I want to do is, I did get some finger marks on this earlier, so I'm just ribbing down a little bit farther because I wanted to have that a little bit cleaner. So there we go. There's the trimmed foot ring using a chum. Now, the cool thing about this chum is if I wanted to just carefully clean off all of these leather hard pieces and I wanted to maybe rib off if there's anything that's dry on here, I could then take that chum and throw it into another piece. If I wanted to use this chum to trim again, what I usually do is I'll just rib it one more time, put my lines back on there. If it needs to be re-centered, re-center it, put my lines back on there, and then I can anchor my next piece on there. I love chums because you can use them over and over and over. The next method of trimming that I'm going to show is using lugs. I'm going to start off by cleaning off the bat first. And then I have three hunks of clay. These are often just referred to as lugs, like chunky coils if you will. And I'm going to first of all get this approximately in the center. I'm using a method here that's called tap centering to center this. Tap centering takes a little bit of practice to get used to. One of the things that I sometimes do is I have had bats where I put lines on it in marker for the kids. So you could also do that if you had permanent marker. So now that I have this centered, I'm going to lay down these three lugs surrounding it. So it's going to have three points that are going to be holding this in place. Now this pot is fully leather hard. So by doing this, I should not mess up the rim of it. If your clay is too soft, you can mess it up at this point. So now with these lugs in place, I'm trying not to move the cup at all. I just want to smoosh these lugs so they are firmly attached to the bat. And let's just spin that again, make sure we still look good there, yep. And these lugs are just going to hold the rim of the cup in place as I trim. This is the way that I learned when I first was in college. I learned how to trim using just lugs. Now same, all the trimming tips apply as far as lock that tool to your left hand, go straight down for the exterior of the foot, have both hands locked together, and actually touch the left hand to the pot bottom. That helps to be really even. I decided to speed this part along because it's just reviewing what I've already shown. I am just now refining the profile and trying to get rid of any lines, making sure that the wall is nice and even. And then I want to compress. I'm using Red Rib, you could always add a little water with a sponge, and then I'm compressing the edge. Now I'm tapping the middle to see how thick that is, and I'm going straight down from the bottom to cut the inside of the foot. Now this pot is relatively thin, so I'm not trimming all the way across the middle. By tapping, I can tell how thick it is, and I know it has a little give that that's as thick as I want to make it. Now I'm removing the lugs, and I'll keep those. I'm just removing the leather hard scraps, and I can wedge that up. And now I'm just going to smooth the upper rim with a little bit of water, and then use a wet chamois. The next method is going to be trimming on a sticky bat. Now the sticky bat is already mounted onto a bat. You want to use the appropriate bat pin holes to make sure that it fits on your bat or on your wheel head. And then, you can see that I have taken a marker, and I have put some concentric circles on there to help me see where the centered area is going to be. And as I set this on here, I want to make sure that it looks like it's centered in one of those circles. So as I set this on here, I want to make sure that it is centered within the circles there. This is a great little device to use for things like wider things, plates, bowls. For my kids, I don't normally show them the sticky bat for cups, because I think there are more secure ways to hold their pieces. Now because there's nothing holding the outside at all, I am going to use a little assistance here. As I am spinning, I'm just putting a lid down. The lid allows my finger to press without having a real specific spot that perhaps I might be denting in, because I'm pressing down to hold the pot, so I don't knock it off or anything. Now here I'm just going to refine the outer part of the foot. And remember that you don't even have to create a foot on many pieces. You can finish it off on the day that you throw it and not plan on doing a foot. Now don't worry if that cap doesn't look centered. All I'm concerned about is am I keeping the clay centered. I'll move the cap in just a minute. Alright, now I'm going to tidy up the outside with my rib, compress with my finger, kind of lean back, look at it, make sure it's the contour that you like. Now I'm ready to do the interior, and when I do the interior, I'll have to take off that cap. I'm just compressing using a little water with my finger to compress the corner, locking the tool. I go straight down from the top to my hand, locking my hand to the pot bottom, then I round that corner. I like to have a nice rounded appearance. If you ever have a foot that's slightly off-center as well, round the corner, it will help to hide it. I tell my kids that a lot, and they're always amazed at how much it can disguise a foot that might be slightly off. Then I just compress that corner again, and there we go. Got a little chunk there that's not really stuck, it's just sitting there. And then that one is ready to sit aside for a handle. One thing I want to be sure to mention about the sticky bat is you have to make sure that you don't store anything sitting on the sticky bat, or you could damage the surface. You could dent it very easily, because this is kind of a delicate surface. So when I'm done washing it, I will be hanging it. I have a little hook that I have on it, and I'll be hanging it so nothing sits on top of it. My last method is going to be with really nothing holding it, besides a little bit of gravity, and I'm adding just a teensy bit of water. You can do this on a bat. I'm doing it right on the wheel head, though. I get that so it looks like it's as centered as I can get it. Here we go. Now this one has a pretty thin bottom, so I know that I have to use this, because if I didn't use this, I could end up kind of poking a hole right through it. So all I want to do here is give it a little bit of trim, and you can see that you can knock it off this way, but... And I'm just tidying up the outside. No foot ring on this. It's going to be a flat bottom because it's pretty thin. Now, because this one doesn't have a foot ring, I do have a little bevel on it, though. That bevel is going to be the part that I will not glaze eventually. That's kind of the indicator of where to either stop glazing or where to wax it so I don't get glaze on it. And that one, with a flat bottom, all done. I do want to mention the tools that I have been using for the trimming. I do like a small little mud tools rib, whether it's soft, a little bit firmer, or even the little metal scraper. I think the Zayam Company or Sim Company, they also have some that are somewhat similar, but mud tools, those are the originals. I really like those a lot. You might want a cap of some sort, or just a little disc of something where it can spin underneath. You'll want a sponge with a little bit of access to some water, and then you will want a trim tool. Now, trim tools are in all sorts of different designs. This Kemper tool is the inexpensive student grade one that we use in my classroom studio. They don't last forever. I do have to replace them because the metal will wear out. We use grogged stoneware in my classroom, and it will wear them down after a little bit. Another really important thing that I want to emphasize that I don't think I really talked about is the importance of trimming your pieces while they're hard. As you trim it, it should come off in ribbons. If it is dry, and you're trying to trim something bone dry, and it's coming off in dust, that poses a big danger. Breathing in dust is dangerous because silica dust, silica microcrystalline dust, gets in your lungs, and you can't expel it. Now, for someone who is working on pottery for, you know, 40, 50 years, that could be really bad. In my classroom, if someone has a bone dry piece, I tell them don't even try to do it. You could put it in a damp box, bring it back to a leather hard state. It might take a couple of weeks, but it's often just easier just to rethrow something. But don't trim when it's bone dry. You will have dangerous dust that goes into the air, and it makes a mess all over the floor. It's just a nuisance. I did want to mention what I often do with my scraps. So after I'm done trimming, I usually try to collect those scraps before they dry out, and I put them in a bucket, or perhaps even a bag, and then I'll squirt them down generously. And that way, they can sit, reabsorb the water, and then I can wedge them like the following day. In addition to those five methods, there are two others that I just want to mention, even though there's no reason that I would use them for the cups. One would be using a foam bat. So you can take foam rubber and attach it to a bat. You can also make concentric circles on it, and then you can place your item on there. Again, this wouldn't be good for a cup, but it would be great for, like if you have a big platter or a big bowl with an irregular rim, it can really protect it. And the other would be a chuck. Now, chucks can be thrown directly on a bat, and they can be used right away, but a chuck, again, I wouldn't really use that for a cup. A chuck is good for a form that maybe has a narrow neck. So like if I were going to trim a bottle like this, I could make a chuck that kind of comes up and goes right there in that, at that shoulder. This would be like for something really wide, right, that has a neck that fits in there. But something where you don't want to set it on its neck because it might compromise the integrity of it, that's a chuck. If you have trouble remembering the difference between what's a chuck and what's a chum, if you think about how a drill has a chuck on it that opens to accept the drill bit, maybe that will help. Chucks, you know, open and close. Thanks for tuning in today. I hope you enjoyed this. If you have any questions, just drop them below. And don't forget to like and subscribe, and I'll see you next time.